Mechanical stoker



E. S. WALLEN.

MECHANICAL STOKER.

APPLICATION FILED OCT. 8. 1917.

Patented May 11, 1920.

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MECHANICAL STOKER.

APPLICATION FILED OCT-8| 1917.

1,339,531, Papehted May 11,1920.

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UNITED STATES PATENT OFFICE.

EARL S. WALLEN, OF LANSFORD, PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGH' MENTS, '10 COXE TRAVELING .GRATE COMPANY, OF HAZLETON, PENNSYLVANIA,

A CORPORATION OF PENNSYLVANIA.

MECHANICAL s'roKEa.

Specification of Letterslatent,

Patented May 11, 1920.

Application fi led October a, 1917. Serial No. 195,412.

To all whom it may concern:

Be it known that I, EARL S. VVALLEN, a citizen of the United States, residin at Lansford, in the county of Carbon and tate of Pennsylvania, have invented. certain new and useful Improvements in Mechanical Stokers; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in mechanical stokers and more particularly to that type employing a traveling grate and means for forcing air pressure upwardly therethrough, and the object is to provide simple and inexpensive means to prevent the leakage of air pressure around the ends of the grate bars. This leakage has heretofore blown the powdered coal or the like away from the side walls of the firebox and caused the fire to be poor along the sides, and the excess draft at this point has been found to fuse clinkers to the brickwork, thus lowering the efliciency of the furnace greatly. Fine coal also falls down through the grate bars onto the chain rail and the escaping air pressure blows this coal out of the front of the furnace onto the floor, thus meaning the continual expenditure of time and labor in removing this leakage.

\Vith the foregoinggeneral object in view, the invention resides in certain novel features of construction and unique combinations of parts to be hereinafter fully described and claimed, the descriptive matter being supplemented by the accompanying drawings which form a part of this specification and in which:

Figure 1 is a stoker embodying construction; V

Fig. 2 is a horizontal section showing a top plan view of a portion. of the traveling grate;

Fig. 3 is a vertical transverse section on the plane of the line 33 of Fig. 1;

Fig. 4 is an enlarged top plan of one end of a pair of the grate bars, showing more particularly the arrangement of air sealing webs thereon;

Fig. 5 is a transverse section of one of the grate bars on the plane of the line 5-5 of Fig. 1; and,

the improved features of longitudinal section of a Fig. 6 is a perspective view of one end of one of the grate bars.

In the drawings above briefly described, the numeral 1 designates a firebox whose bottom is formed by a traveling grate 2, said grate including a pair of side chains 3 and transverse grate bars 4: joined at their ends to said chains, the usual chain rails 5 being provided for supporting said chains as they travel between the drums 6 at the front and rear of the furnace. Fuel'such as slack is fed to the traveling grate 2 through a hopper 7 at the front end of the furnace and air pressure is supplied beneath the upper reach of said grate by any preferred means such as the usual wind box Shaving the well known air connections 9.

As above stated, considerable leakage of air has heretofore occurred around the ends of the grate bars 4, itbeing the intention ofthe present improvements to check this leakage in so far as'possible. To this end, I provide seal plate means consisting of a pair of longitudinal plates or ledges 10 which extend inwardly beyond the chain rails 5 and equip the grate bars a with outer and inner air sealing ribs or webs 11 and 12 respectively which travel on said ledges as shown clearly in the drawings. By this arrangement, any air leaking past the inner webs 12 will be checked by the outer webs l1 and will thus be given a chance-to rise through the grate bars rather than leaking past said webs 11 and around the ends of the bars. I have found by this arrangement, that the leakage of air around the ends of the grate bars is so reduced as to positively prevent all of the undesirable results above enumerated.

The outer webs 11 which extend transversely of the grate bars 4, have their opposite ends offset laterally, so that the several webs will overlap as shown clearly in Fig. 2. One end of each web. 11 extends beyond one edge of the grate bars, whereas the other end thereof terminates flush with the opposite edge of said bars, the latter being provided with vertical notches or sockets 13 so that the projecting ends of each web 11 will be received in the socket 13 of the adjacent grate bar. By this arrangement, it is practically impossible for the air to leak past the several webs, even though a slight amount of this air should pass the webs 12.

The last named webs extend beyond the grate bars at one end, whereas their other ends are formed with vertical notches or sockets 14, the projecting ends of said Webs being received in the sockets of the adjacent grate bars as illustrated in Fig. 2, so that an effective air seal is provided. The projecting ends of the webs 11 and 12 are disposed in vertical planes as shown clearly at the left of Fig. 5, but in order that the grate bars may properly angle when the grate passes around the drums 6, the inner walls of the sockets 13 and 14 diverge downwardly from said ends. This is shown most clearly at the right of Fig. 5 and in Fig. 6. V o The usual keys 15 are dovetailed at 16 upon the grate bars 4 in the well known manner, the lower sides of said keys having the usual grooves 17 which extend transversely of the line of travel of theconveyer or grate; and in order to seal these grooves to prevent air from leaking therethrough above the ribs 12, the upper edges of said ribs are provided with upstanding projections 18 which are snugly received in the grooves as disclosed in Fig. 1.' If desired,

the webs 11 may also be provided-with projections such as those indicated at 19, but in most cases this is unnecessary since the endmost keys abut the chain 3 and thus prevent the leakage of air excessively at this point.

From the foregoing, taken in connection with the accompanying drawings, it Will be obvious that although my invention is of extremely simple and inexpensive nature, it will be highly efiicient and durable for the purposes intended, that is for preventing the leakage of air around the ends of the grate bars. Since probably the best results are obtained from the specific construction shown and described, this construction constitutes the preferred embodiment of the device. I wish it understood that within the scope of the invention as claimed, numerous minor changes may well be made without sacrificing the principal advantages.

I claim:

1. In a mechanical stoker, the combination of a firebox, a traveling grate forming the bottom of said firebox and including side chains and transverse grate bars supported thereby, and ledges upon which the ends of said grate bars slide, said grate bars being provided at their ends with transverse air sealing webs contacting with said ledges, and with additional transverse air sealing witnesses.

webs spaced inwardly from said first named webs and also contacting with said ledges.

2. In a mechanical stoker, the combination or a firebox, a traveling grate forming the bottom of said firebox and including side chains and transverse grate bars supported thereby, and ledges upon which the ends of said grate bars slide, said grate bars being provided at their ends with transverse air sealing webscontacting with said ledges, one end of each web extending laterally from one edge of the grate bar, whereas the opposite edge of the bar is provided with a vertical notch, the projecting ends of the several webs being received in the notches of adjacent grate. bars, said grate, bars also having additional transverse air'sealing webs spacedinwardly from said first named webs, said additional'webs being disposed in sliding contact with said ledges and having one end extending beyond one side of the grate bars, whereas the other ends of saidw'vebs are each formed with a vertical notch, the projecting ends of said last named webs being received in the notches of the adjacent webs,

substantially as and for the purpose speci- 3. In a mechanical stoker, the combinationof a firebox, a traveling grate forming the bottom of said firebox and including side cliains'and transverse grate barssupported V 7 thereby, keys on sa d grate'bars-havmg the usual grooves in their inner faces, and ledges upon which the ends of the grate bars slide, said grate bars being provided at their ends with transverse air sealing webs contacting with said ledges and with additional transverse air sealing webs spaced inwardly from said first named webs and also contacting with said ledges, the upper edges of said additional webs having projectlons extending into and sealing said grooves. 4. In combination with a traveling grate a wind box subjacent the working portion of the grate, seal plate means at the sides of the wind box and closely spaced sealing ribs at the sides of the grate cooperating with said plate means to afford a double seal at the side margins of the grate. v

In testimony whereof I have hereunto set my hand in the presence of two subscribing K V EARLS. WALLEN.

lVitnesses-z V HA Y CLASE PnLrz, A. A. STOFFLET. 

